Features like transitive dependencies and the new parent specification mechanism. The problem we run into is
 that currently we have information about a project scattered across the project.xml and the
 various properties files. What needs to be done is to encapsulate all of this in the POM.

 Typically users parameterize the use of plugins, or have custom values like ${user.name}

    For example, you could use it to read and verify passwords generated by another system (like Django) but hash any new passwords with a different algorithm like Bcrypt.

    And be compatible with all of them at the same time.

Create a utility function to hash a password coming from the user.

<div class="termy">

```console
$ OPENAPI_URL= uvicorn main:app

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

Then if you go to the URLs at `/openapi.json`, `/docs`, or `/redoc` you will just get a `404 Not Found` error like:

```JSON
{
    "detail": "Not Found"
}

going to shrink any further:  she felt a little nervous about
this; `for it might end, you know,' said Alice to herself, `in my
going out altogether, like a candle.  I wonder what I should be
like then?'  And she tried to fancy what the flame of a candle is
like after the candle is blown out, for she could not remember
ever having seen such a thing.

  After a while, finding that nothing more happened, she decided

* 可获取上传文件的元数据；
* 自带 <a href="https://docs.python.org/zh-cn/3/glossary.html#term-file-like-object" class="external-link" target="_blank">file-like</a> `async` 接口；
* 暴露的 Python <a href="https://docs.python.org/zh-cn/3/library/tempfile.html#tempfile.SpooledTemporaryFile" class="external-link" target="_blank">`SpooledTemporaryFile`</a> 对象，可直接传递给其他预期「file-like」对象的库。

### `UploadFile`

`UploadFile` 的属性如下：

But that file doesn't exist, our dependencies are in a file at `app/dependencies.py`.

Remember how our app/file structure looks like:

<img src="/img/tutorial/bigger-applications/package.svg">

---

The two dots `..`, like in:

```Python
from ..dependencies import get_token_header
```

mean:

Later, for your production application, you might want to use a database server like **PostgreSQL**.

!!! tip
    You could adopt ideas from the section about SQLAlchemy ORM ([SQL (Relational) Databases](../tutorial/sql-databases.md){.internal-link target=_blank}), like using utility functions to perform operations in the database, independent of your **FastAPI** code.

* Caddy
    * Automatically handles certificates renewals ✨
* Nginx
    * With an external component like Certbot for certificate renewals
* HAProxy
    * With an external component like Certbot for certificate renewals
* Kubernetes with an Ingress Controller like Nginx
    * With an external component like cert-manager for certificate renewals
* Handled internally by a cloud provider as part of their services (read below 👇)

## Multiple body parameters

In the previous example, the *path operations* would expect a JSON body with the attributes of an `Item`, like:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2
}
```

But you can also declare multiple body parameters, e.g. `item` and `user`:

  implementation of the BasicComponentConfigurator. This ExpressionEvaluator
  simply returns the expression itself as the resolved value, which adds
  very little value to the container. Things like ${project.build.resources}
  are not resolved, and result in a type mismatch for the member injection.

  We need a replacement for DefaultExpressionEvaluator that is capable of